The present invention relates to a wiring board having terminals for use in connecting circuit boards in various kinds of electronic devices.
In recent years, many kinds of flexible wiring boards are employed to connect a plurality of circuit boards, having electronic components, in various kinds of electronic devices, or to connect circuit boards and motors or elements and the like.
Along with technological advances in electronic devices with high performance and downsized design, wiring boards are required which can carry an increased number of wiring patterns and have a downsized design with narrow distance between patterns that are so-called narrow-pitched patterns.
Now, a conventional wiring board having terminals is described with reference to FIG. 5. The figure is shown on an expanded scale in a thickness direction for easy understanding of the configuration.
FIG. 5 shows an exploded perspective view of a conventional wiring board. A thin layer of copper alloy or the like is etched to form a plurality of wiring patterns 2 on a top surface of flexible film-base substrate 1 composed of polyethylene terephthalate or the like, and the entire surfaces of wiring patterns 2 are covered with an insulating layer composed of polyester resin or the like, except for connecting sections 2A and 2B which are located at both ends of each wiring pattern 2.
Additionally, thin-metal-sheet terminal 5 having coupling section 5A formed with an approximate T-shape on one end is placed on the top surface of one end of connecting section 2A of base substrate 1. And, the bottom surface of flexible film-base top substrate 6 composed of polyethylene terephthalate or the like is coated with anisotropic conductive adhesives (ACA) 7 in which conductive powder made of polyester powder or nickel powder plated with noble metal is dispersed.
A wiring board having the above configuration is manufactured according to the steps of:
(a) placing coupling section 5A of thin-metal-sheet terminal 5 on connecting section 2A of base substrate 1;
(b) stacking top substrate 6 on which ACA 7 is applied previously on connecting section 2A; and
(c) heat-pressing from an upper side of top substrate 6.
Upon using the aforementioned wiring board for electronic devices, for example, lead wires for motors are soldered to one end of each terminal 5, and another end 2B is connected to a circuit board.
This configuration can connect a motor and a circuit board via terminals 5, anisotropic conductive adhesives 7 and wiring patterns 2.
In the above conventional wiring board, coupling section 5A which is held between base substrate 1 and top substrate 6, must be approximately T-shaped with protrusions on both sides of the terminal, and must apply ACA 7 around the protrusions 5B, to provide terminal 5 with a required pull-out strength in a direction shown by an arrow in FIG. 5.
Along with advances in high-density electric devices, which are required to have an increased number of wiring patterns, difficulty is caused in designing narrow-pitched patterns, because coupling sections 5A, having protrusions on both sides of approximately T-shaped terminal 5, occupy large spaces uselessly.
In other words, conventional wiring boards have drawbacks in providing narrow-pitched patterns for downsized designing.
The invention disclosed can provide a wiring board having terminals capable of downsizing as wiring patterns are formed at a narrow-pitch while keeping the pull-out strength of the terminals unchanged, to solve the aforementioned problems.
A wiring board disclosed in this invention comprises:
(a) a first substrate having a first surface, which forms a wiring pattern provided with a connecting section;
(b) a second substrate, which faces said first surface via anisotropic conductive adhesives; and
(c) plate-shaped metal terminal provided with a coupling section placed on said connecting section between said first substrate and said second substrate, wherein said coupling section has one of a bar-shape and an L-shape, and has an unevenly formed surface.